1. Field of the Invention
The present invention relates to an electric vehicle, a management apparatus, and a drive management method.
2. Description of the Related Art
In recent years, a technology called a smart grid has been gaining attention. The smart grid is a technological framework to realize efficient power usage by constructing a new transmission network having a communication channel along with the transmission network and using this intelligent transmission network. The background idea of the smart grid is to realize efficient management of power use, swift handling of an incident when such an incident occurs, remote control of power use, distributed power generation using power generation facilities outside the control of a power company, or charging management of an electric vehicle. Particularly, effective utilization of in-house power generating stations using renewable energy by ordinary households or operators other than power companies and charging management of various electric vehicles typically including electric cars have been attracting considerable attention. Incidentally, renewable energy is energy generated without using fossil fuel.
Power generated by ordinary households or operators other than power companies is used by power generation operators. Remaining power after use by the power generation operators is currently purchased by power companies. However, purchasing power supplied from power generation facilities outside the control of a power company is a heavy burden to the power company. For example, amount of power supplied from photovoltaic power generation facilities depends on the weather. Moreover, amount of power supplied from in-house power generating stations of ordinary households depends on power use of ordinary households that largely changes day by day. Thus, it is difficult for power companies to receive stable power supply from power generation facilities outside the control of power companies. For the above reason, it may be difficult for power companies to purchase power in the future.
Thus, a home battery initiative that uses power generated by power generation facilities outside the control of power companies after temporarily storing the power in batteries has recently been gaining attention. For example, a method of using power generated by photovoltaic power generation facilities by storing such power in batteries and making up for shortages in the night or when the weather is bad is considered. Furthermore, a method of limiting amount of power received from a power company in accordance with the battery storage amount or using power stored in batteries in the daytime when power rates are higher by storing power, in batteries, supplied by a power company in the night when power rates are lower are considered. Also, batteries can store power as DC, which makes DC/AC conversion or AC/DC conversion during transmission unnecessary so that losses during conversion can be reduced.
Thus, various expectations regarding power management mingle with one another amid the smart grid initiative. To realize such power management, the smart grid initiative is premised on having a communication channel along with a transmission network. That is, exchanging information about power management by using this intelligent transmission network is assumed. However, in a region where a communication infrastructure is already built, instead of using a transmission network as a communication channel, information about power management may be exchanged by using a network constructed by the deployed communication infrastructure. That is, what is important in the smart grid initiative is how to efficiently manage power generation facilities and storage facilities that are not uniformly managed.
The power management in the smart grid initiative includes, as described above, charging management of an electric vehicle. A typical example of the electric vehicle (EV) is an electric car. However, in addition to the electric cars, for example, electric bicycles, electric buses, electric freight cars, electric ships, and electric planes can also be considered as the electric vehicles. Naturally, the electric vehicles have accumulators or capacitors (hereinafter, denoted as batteries) mounted thereon. Motor-driven movable bodies are driven using power stored in the batteries.
A battery means any unit capable of storing energy in some form and discharging energy again. Typical examples thereof include accumulators and capacitors.
As the accumulator, for example, a general accumulator such as a lithium-ion battery, nickel-metal hydride battery, lead storage battery, and NAS battery can be given as examples. Moreover, in addition to these general accumulators that can currently be used, any accumulator that will be available in the future can also be used as the accumulator. On the other hand, as the capacitor, for example, a general capacitor such as a field-effect capacitor and ceramic capacitor or a large-capacity electric double layer capacitor under development in recent years can be used.
As a system that stores electrical energy in a re-dischargeable form, a pumped storage generation system can be given as an example. The pumped storage generation system converts electrical energy into potential energy for storage. Then, when re-discharging electrical energy, the potential energy is used to generate power. For example, water is pumped up to a higher place using electrical energy and when discharging electrical energy, hydraulic power generation is carried out using energy that causes the water to fall. Thus, a system that converts electrical energy into potential energy can also be considered as a kind of battery.
As a mechanism to store electrical energy in a re-dischargeable form, a structure that uses electrolysis of water is known. In this mechanism, when storing electrical energy, electrolysis of water is carried out using electrical energy and generated hydrogen is stored. Then, when re-discharging electrical energy, the stored hydrogen is burnt to generate power or the stored hydrogen is used to generate power using fuel cells. Such a mechanism can also be considered as a kind of battery.
As described above, all structures capable of temporarily storing electrical energy by some method and providing electrical energy again can be considered as a kind of battery.
Now, charging facilities set up in ordinary households or charging facilities set up by various operators are used to charge batteries of an electric vehicle. For charging management of electric vehicles from charging facilities, a mechanism that allows the charging facilities to identify each electric vehicle becomes necessary.
Regarding the mechanism of carrying out charging management of electric vehicles from charging facilities, JP-A-2007-228695 discloses a technology of performing authentication of an electric vehicle (car) by using information of an ETC card. The technology of this patent document is for a charging facility to acquire information of an ETC card from an electric vehicle and identify the user of the charging at the time of starting or ending power feeding from the charging facility to the electric vehicle to thereby prevent stealing of power. Furthermore, JP-A-2007-252016 discloses a technology for an electric vehicle (car) to read an ID code from a transponder key of an immobilizer system, authenticate the same, and transmit the authentication result to a charging facility. A transponder key is a key provided with a small electronic communication chip.